Comparación analítica de dos consolidantes comerciales aplicados en areniscas eocenas de monumentos de los siglos XVI y XIX en San Sebastián (norte de España)

The conservation of buildings in the Basque Country made of Eocene sandstone is somewhat problematical, because this type of rock is relatively unstable. This instability is due to the variable content of carbonate cement (0-28%) and the presence of K-feldspar grains (1-13%) which appear to have been dissolved by both diagenetic and environmental processes. We have compared the results of the application of two commercial consolidating products: Sicof SM 296 (product A) and Consistone FS-hA (product B), both ethylsilicates, on Eocene sandstones of the Oquendo Admiral House (16th century) and the Gipuzkoa Provincial Government Palace (19th century), which are both located in the city of San Sebastián (Province of Gipuzkoa, Basque Country, Northern Spain). On the basis of different chemical and physical laboratory tests, together with Scanning Electron Microscopy (SEM) analysis, product A seems to be more efficient in consolidating such Eocene sandstone materials, since it penetrates into the first 8 mm of the rock, occupies very homogeneously even the smallest pore spaces and leaves a certain degree of remaining porosity which allows ventilation of the rock. In contrast, product B seems to be more appropriate for larger pore-sized rocks, because it only penetrates into the first 3 mm of the Eocene sandstone samples due to the thin pores of the matter. Our results demonstrate that the suitability of a commercial product depends not only on its own chemical composition, but also on the textural and lithological features of the rock material upon which it is to be applied.La conservación de los edificios del País Vasco construidos con areniscas del Eoceno es problemática porque este tipo de roca es relativamente inestable debido a su contenido variable en cemento carbonatado (0-28%) y a la presencia de granos de feldespato potásico (1-13%) disueltos tanto por procesos diagenéticos como ambientales. Hemos aplicado dos consolidantes comerciales: Sicof SM 296 (producto A) y Consistone FS+A (producto B), ambos silicatos de etilo, sobre las areniscas de la Casa del Almirante Oquendo (siglo XVI) y el Palacio de la Diputación Foral de Gipuzkoa (siglo XIX), ambos edificios en San Sebastián (País Vasco, norte de España). Los diferentes ensayos físicos y químicos junto con las observaciones al microscopio electrónico de barrido (SEM) revelan que el producto A es más eficiente para la consolidación de este tipo de areniscas, dado que penetra los primeros 8 mm de la roca, ocupa muy regularmente incluso los poros más pequeños y deja un cierto grado de porosidad remanente que permite la aireación de la roca. Por el contrario, el producto B parece más adecuado para rocas con mayor tamaño de poro, dado que sólo penetra los primeros 3 mm. Con ello, queda claro que la eficiencia de un consolidante comercial depende no sólo de su composición química, sino, en gran medida, de las características texturales y litológicas de la roca sobre la que se va a aplicar

Estudio de conservación del material pétreo de la Casa de Cultura del Almirante Oquendo, en San Sebastián

The historical heritage of our country is mainly made up of masonry, playing the sandstones an important role. However, because of the effect of environmental conditions and pollution, these materials can loose their cement, and eventually disintegrate. Chemical consolidants can be applied in order to prevent and stop these decay process, which, when there is a lack of cement, fix the stone grains, enhancing the strength and durability of the In order to ensure the success of the application of these products in restoration works, preliminary studies should he carried out, so as to define the suitability of their use, and select the most appropriate consolidant for each specific case, as the reliability of these products is mainly determined by the microstructure of the stone material under study. This paper describes a study which was carried out on Igueldo sandstone from the main façade of the Casa de Cultura del Almirante Oquendo, in San Sebastian, which aimed at establishing the most suitable consolidation technique for the stone degradation processes observed. Firstly, the study dealt with the diagnosis of the pathologies which affected the stone from this building. Furthermore, 6 commercial consolidants were tested on quarry stone. Finally, the results were validated applying these products in real work conditions, what enabled us to select the most appropriate treatment for the restoration of the main façade of the building.El Patrimonio Histórico-Artístico de nuestro país, está constituido, principalmente, por edificios de piedra de sillería, en los que las areniscas juegan un papel muy importante. Sin embargo, debido, fundamentalmente, a las condiciones medioambientales y a la contaminación, estos materiales pueden perder su matriz cementante y sufrir una desintegración. Para prevenir y frenar estos fenómenos de deterioro, se pueden emplear productos consolidantes que, en ausencia de matriz cementante, fijan los granos del material pétreo, proporcionando resistencia y durabilidad al sillar. Para asegurar la fiabilidad de las intervenciones realizadas con estos productos, es necesario llevar a cabo unos estudios previos, al objeto de definir la idoneidad del empleo de consolidantes y seleccionar el tipo más adecuado para cada caso concreto, ya que la fiabilidad de estos productos depende, en gran medida, de la microestructura del material pétreo considerado. FA presente artículo recoge un estudio llevado a cabo sobre la arenisca de Igueldo de la fachada principal de la Casa de Cultura del Almirante Oquendo, en San Sebastián, con el fin de determinar el tratamiento de consolidación más adecuado para la alteración observada en este material pétreo. FA estudio realizado consistió, en primer lugar, en la diagnosis de las patologías presentadas en el material pétreo de este edificio. Posteriormente, se ensayaron 6 productos consolidantes comerciales sobre piedra inalterada de cantera. Por último, se validaron los resultados obtenidos, mediante ensayos en el monumento de los 3 tipos de consolidantes más adecuados, aplicados en condiciones reales de obra, eligiendo el tratamiento más idóneo para la restauración de la fachada principal del edificio

Professional development programmes for teachers moving from majority to minoritised language medium education:Lessons from a comparative study

Education through the medium of a minoritised language is widely regarded as a critical component of language revitalisation initiatives. Given the demographic and social position of many minoritised languages, however, it may not be easy to find teachers who are fluent and literate in the language, confident about using and teaching it, and prepared for the demands of working in classrooms where the language is the medium of instruction. This article presents findings from a comparative study of teacher education programmes adopted in Catalonia, the Basque Autonomous Community, Wales and New Zealand, to prepare teachers to teach through the media of Catalan, Basque, Welsh and Māori respectively. The research was conducted to inform new professional development initiatives in Scotland, designed to enable qualified teachers to transfer from English-medium to Gaelic-medium education. The findings have wider relevance for other contexts in which the recruitment, professional development and retention of teachers to work in minoritised language medium education represent a challenge

Petrography, provenance and alterability of the stone material used for the construction of the St Millán de la CogoIIa Monastery, Yuso (16th to 17th centuries), La Rioja

A catalogue of the stone material employed for the construction of the San Millán de la CogoIIa Monastery (Yuso) has been undertaken. The characterization of the rocks has enabled us to explain the provenance of the most part of the stones from several quarries very close to the monastery. We have also compared the different degree of alteration of the stone material. Whereas the brecciated limestones from Jurassic age employed for the construction of all the main walls and columns of the monastery, have a very resistant behaviour to weathering, the Tertiary sandstones and coarse-crystalline evaporites (gypsum) were destined to archs, archivolts, cornices and ornamental pieces and appear largely affected by dissolution processes showing a high degree of decomposition, particularly in the northern and western façades of the building. The evaporitic material has been specially conflictive with respect to the restoration works carried out the last year on this historic monaster

S.E.M. Applications to the study of the damage and restoration of historic buildings: the Oquendo House (16th century) and the Deputation Palace (19th century) (San Sebastián, Basque Country)

The studies on the deterioration and restoration of buildings have increased in the last decades. The role of Scanning Electron Microscopy (S.E.M.) as a tool for textural studies of both damaged and restored rocks is important since it enables to us to identify both the style of penetration of consolidating products inside altered rocks and the solidification textures into pore spaces. We have compared the results of the application of the products Sicof SM 296 and Consistone FS+A on Eocene sandstones of the Oquendo House and of the Deputation Palace, both buildings at San Sebastián city. As observed from S.E.M. and different laboratory tests, the Sicof SM 296 seems to be the most efficient consolidating product for the restoration of such Eocene sandstone materials since it occupies even the smallest pore spaces very homogeneously and leaves a certain degree of remaining porosit

Technical management risks for transport infrastructures along whole life cycle: identification and intervention

RAGTIME is a Horizon 2020 project focused on development, demonstration and validation of an innovative infrastructures management approach. It lays out a whole system, based on standard multi-scale data models, able to facilitate a holistic management throughout the entire lifecycle of the infrastructure, providing an integrated view of risk based approach, implementing risk based models, resilient concepts and mitigation actions. It is structured in three modules: governance, finance and economic, and technical management. This paper is focused on RAGTIME’s technical management module. The main objective of this paper is to deal with technical risk assessment of the transport infrastructure approach based on an innovative 3D vector, defined by following variables: stakeholder (owner/citizenship, contractor and financier), life-cycle phase (evaluation-planning, procurement-decision, design-project, construction, and operation and maintenance) and infrastructure (rail, road, port and airport)This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 690660

Fatigue Strengthening of Steel Bridges with Adhesively Bonded CFRP Laminates: Case Study

One of the aims of applying sustainable development to bridge infrastructure was to provide bridge owners with strengthening solutions that could lead to increased service life for existing structures. In the case of steel bridges, the assessment of the remaining service life is most often linked to the determination of structural deterioration caused by corrosion and fatigue. Damage caused by fatigue is very difficult to assess before crack initiation and is more likely to occur in older structures, where the phenomenon was not taken into account in designs before 1970. In addition, old steel materials display more brittle behavior. To meet these challenges, a preventive methodology for fatigue strengthening of steel structures was developed. The method begins with scheduling a fatigue design analysis of the existing construction to determine the most fatigue damage exposed construction elements of the bridge. The remaining fatigue life of these elements can be increased with a strengthening solution based on the use of adhesively bonded ultra-high modulus (UHM) carbon fiber–reinforced polymer (CFRP) plates, which were applied to a steel surface before failure indicators such as cracks arise. This article presents the development process of this preventive method and a demonstrative application to an existing bridge (Jarama Bridge). Strain measurement was carried out to verify the theoretical expectations of the reinforcement. Different parameters were studied, including the influence of low traffic volumes during the reinforcement application. The results proved the efficiency of this system for the structure under study